1. Field of the Invention
The present invention relates to an air intake control valve and an air intake apparatus.
2. Description of the Background Art
In general, an air intake control valve including a valve body to open and close a fluid passage is known. Such an air intake control valve is disclosed in Japanese Patent Laying-Open No. 2008-144768, for example.
In the aforementioned Japanese Patent Laying-Open No. 2008-144768, there is disclosed a control valve (air intake control valve) including a frame-shaped body (frame) formed with an air intake passage (fluid passage) and a valve (valve body) supported by the frame-shaped body, rotated between an open position and a closed position to open and close the air intake passage of the body.
Furthermore, in general, the structure of a surge tank of an internal-combustion engine internally divided into two spaces by a partition wall, in which the conventional control valve (air intake control valve) described in the aforementioned Japanese Patent Laying-Open No. 2008-144768 is provided in an opening portion formed in the partition wall in order to change the resonance frequency of an air intake system to obtain an effective supercharging effect in a wide engine operation range, is known. In this structure, the frame-shaped body (frame) in a state where the valve is mounted thereon is fitted into the opening portion of the partition wall, the two spaces in the surge tank communicate with each other through the air intake passage formed in the body by rotating the valve supported by the body to the open position, and the two spaces are separated from each other by rotating the valve to the closed position to close the air intake passage.
In the aforementioned conventional structure, however, the air intake passage formed in the frame-shaped body (frame) fitted into the opening portion formed in the partition wall is opened and closed by the valve, and hence there is such inconvenience that it is difficult to sufficiently increase the opening area of the air intake passage opened and closed by the valve. In other words, it is difficult to enlarge the opening portion of the partition wall in the surge tank having a limited space and it is necessary to fit the frame-shaped body into the opening portion, so that the opening area of the air intake passage (fluid passage) is reduced by the width of the frame-shaped body from the opening area of the opening portion of the partition wall. Therefore, when the valve is so rotated to the open position that the two spaces communicate with each other, the opening area of the air intake passage is reduced so that the pressure loss of intake air circulating through the air intake passage is increased. Thus, there is such a problem that the amount of intake air circulating through the air intake passage is reduced and a sufficient supercharging effect cannot be obtained. Furthermore, in the aforementioned conventional structure, the frame-shaped body is fitted into the opening portion of the partition wall in a state where a gasket is generally provided along the outer peripheral surface of the frame-shaped body in order to prevent intake air from leaking from a clearance between the inner peripheral surface of the opening portion of the partition wall and the outer peripheral surface of the frame-shaped body (frame). In this case, the opening area of the air intake passage (fluid passage) is reduced by the thickness of the gasket in addition to the width of the frame-shaped body (frame), and hence there is such a problem that the amount of intake air circulating through the air intake passage is further reduced.